Originally I started as a Human, because the alternative I'd really wanted simply wasn't yet an option in the game. I've tried NElf and Dwarf, and both bothered me for different reasons... (Draenei didn't exist yet)

Now I'm a Gnome. Because I'd always wanted to be a WoW Gnome, so the day it became available I transformed. Why Gnome? Because I like small characters, and WoW's Gnomes appeal to me. Sometimes I miss having gear that doesn't look super deformed on my character, but not enough to switch back.

"Bananas, like people, sometimes look different when they are naked." Grace Helbig

Well made it in TBC, took it as Human for the 10% spirit bonus it gave then which was a nice bonus when all Priests were holy. I faction swapped in TBC for something to do, BE for the same reason, arcane torrent. Then went back when i started it as my main in cata to human for the same reason. Although the spirit buff is now only 3%, when cata launched regen mattered.